Sheet-metal hollow ball and method of making the same.



' J. H. GRUVER.

SHEET METAL HOLLOW BALL AND METHOD OF MAKING THE SAME.

. APPLICATION FILED APR.12,19|T. 1,78,914.

2 7% Atty.

Patented Sept. 17, 1918.

4 SHEET'SHEET I.

Inventor: 72h Graver e L E A w L L A W J. H. GRUVER.

SHEET METAL HOLLOW BALL AND METHOD OF MAKING THE SAME.

APPLICATION FILED APR. 12. m7.

1,27,914. Patented Sept. 17,1918

4 SHEETSSHEET 2.

in H. GR UVER. SHEET METAL HOLLOW BALL AND METHOD OF MAKING THE SAME.

. APPLICATION FILED APR- 12. I917. igm ma SHEET 3.

Sep

4 SHEETS Patented 3. HrGRUVER.

SHEET METAL HOLLOW BALL A'ND'METHOD OF MAKING THE SAME.

APPLICATION FILED APR.12.19II.

4 SHEETS SHEET 4.

mm 1 9 1 7n 1 uu' m d. 6 m 6 m .0

Zmwentnr:

JOSEPH HARRY GRUVER, OF BALTIMORE, MARYLAND.

SHEET-METAL HOLLOW BALL AND METHOD OF MAKING THE SAME.

Specification of Letters Patent.

Patented Sept. 17, 1918.

Application filed April 12, 1917. Serial No. 161,603.

To all whom it may concern: 7

Be it known that I. Josnrn HARRY GRUVER, a citizen of the United States, and resident of Baltimore, Maryland, have invented certain new and useful Improvements in Sheet-Metal Hollow Balls and Methods of Making the Same, of which the following is a specification.

The object of this invention is to provide a hollow sheet metal ball of one piece of metal, the ball being closed and of perfectly spherical form having no seam or joint.

. The invention consists in the article produced and in the method for making the article.

In the accompanying drawings,

Figure 1 shows a part of a die or press for performing the first step in the formation of a cup-shaped blank.

1*" illustrates the blank in sebtion. as produced by the dies of Fig. 1.

Fig. 2 is a sectional view of a part of a press for performing the second operation.

Fig 2 is a view of the blank as produced by the apparatus of Fig. 2.

Figs. 3, 4. 5 and 6 are views of presses, in section. for performing other successive steps on the blank, and,

Figs. 3*, 4, 5 and 6 represent respectively the blanks as produced by the presses of Figs. 3, 4, 5 and 6.

Fig. 7 shows a die which when substituted for the die shown in Fig. 6 willperform another step action on the blank.

Fig. 7 is a view of the blank as produced with the aid of the die of Fig. 7

Fig. 8 is a view of a partly rolled blank illustrating the fact that the opening is partly closed as a consequence of a rolling action on the blank of Fig. 7

Fig. 9 is a sectional view of the completed ball, as it comes from a second rolling operation.

Fig. 10 illustrates a machine for performinga rolling action on the blanks.

Referring to Fig. 1 this is illustrative of any suitable press that may be employed for shaping the blank up into cup-form, as shown in Fig. 1. After this first operation is performed the cup-shaped blank is subjected to the action of the press shown in Fig. 2, which elongates the cup and forms a flaring flange a thereon, as shown in Fig. 2*. This cup is smaller in diameter than the cup shown in Fig. 1* and is considerably longer. Any suitable form of press may be employed in performing this operation of Fig. 2 such as shown in Fig. 2. and a knock-out pin shown at b operated in any suitable manner after the die operation has been performed is utilized to eject the blank. This blank is then placed in a shearing press shown in Fig. 3 and comprising a plunger 0 having a shearing edge at d and cooperating with the shearlng edge e on a die f, so that the flange a of Fig. 2 will be trimmed off to provide a face a at the outer side of the flange a, said face a being of cylindrical form and concentric with the wall of the cup, but lying in a circle larger in diameter than the outer side of the cup wall. This shearing action not only prov-ides this cylindrical outer face a, but it trims off the surplus of metal of the flaring rim a. This trimmed off portion is in the form of a ringand in order to effect its ready discharge from the machine a knife-edged pin 9 is provided which comes down on this trimmed ofl ring and seVeI's it into two sections for their ready removal. The face a which is formed by this cutting or shearing action lies in a plane at a sharp inclination to the plane of the inner face a of the rim, as shown in Fig. 3. This forms a sharp edge at a.

The next step in the operation consists in upsetting the flaring flange or rim or in other words straightening it up into line with the wall of the cup so that, the blank will then appear as in Fig. 4 and the in clined edge face a will now be lying between the planes of the inner and outer faces of the wall of the cup, and this inclined face will be at an angle of substantially forty-five degrees to the axis of the cup. The ress for performing this upsetting or straightening up operation on the flaring flange or end of the blank consists simply of a die it and a plunger z','it being understood that in order to illustrate the present method it is assumed that the blanks are placed in the presses by hand.

.The next. step consists in reducing one end of the cup-like blank to form a body as shown in Fig. 5 with an inwardly turned wall or portion at a and a straight-necked portion at a this neck: portion terminating in the beveled edge a, above men tioned.

As above stated, this blank of Fig. 5 is formed by the press shown in Fig. 5.

The next step consists in turning inwardly the neck portion a of Fig. 5 so that the blank will then assume the formof Fig. 6*. As above stated the form shown in Fig. 6* is produced by the press of Fig. 6.

Fig. 7 represents the blank resulting from the next step in the operation, it having now assumed a form approximating that of a ball, though not being a perfect sphere. This form results from the use of the die of Fig. 7 when substituted for the die 70 of Fig. 6 and used in a press like the press shown in said Fig. 6.

It will of course be understood that in carrying out the operation to form the blank of Fig. 7 a separate press from that-shown in Fig. 6 will be used but this press difl'ers only from that shown in Fig. 6, as stated above, by the substitution of the die j for the die 70. The blank of Fig. 7 is now annealed or softened to render it fit for the subsequent rolling operations. This blank has a small hole indicated at a and it will be observed that because of the inclined face of the edge of the blank this hole will be of a tapered form with the small diameter portion nearest to the center of the blank. The blank of Fig. 7 is now placed with a large number of others of like form'in grooves of the plates 1 and 2 Fig. 10,- and a rolling action is performed on the blanks by the relative rotation of these plates, the plates meanwhile being pressed toward each other. This rolling action reduces the blanks slightly in diameter and partly closes the opening therein. The blank, after this first rolling action is performed thereon, assumes the form shown in'Fig; 8, in which it will be noticed that the inner sharp corner of the inclined end or edge face a of the blank is brought together from all directions and the closing action of the opening has been started. After this first rolling action is completed the blanks of Fig. 8 are again annealed to prepare them by softening for the second or final rolling action. This final rolling action is performed by apparatus similar to that shown in Fig. 10 in which, however, the groove or grooves in which the partly completed balls are rolled are of smaller diameter than the groove or grooves of the first rolling machine.

The result of this second rolling action is illustrated in Fig. 9 in which it will be observed that metal has accumulated-on the interior of the blank at the point where the opening is closed or in other words at the point where the circular edge of the blank is pressed from all directions towardone point.

It will be observed by comparing Figs. 8 and 9 that the tapered recess in the blank of Fig. 8 is by the second rolling action filled up by crowding or swaging or flowing the metal over into this inwardly tapered recess and the surplus metal flows inwardly, as indicated at cf, Fig. 9, where it remains without detriment to the structure or use of the ball. By this method of operation there will be no tendency for the metal to lap on the outer side of the ball in a thin layer and there will be no action resulting, such as closing the opening with a thin film of metal on the outside in the form of.a layer leaving the inner parts of the openin unfilled.

In the present process the rst closing of the opening takes place at the innermost part of the wall or the meeting edges of the blank and this is fbllowed by a gradual filling up of the conical opening from the interier. to the exterior of the ball, so that the final product will have its wall closed or united for the full thickness of the shell, and furthermore, there will be extra thickness of metal at this point, due to the flowing inwardly of the metal, as shown at a, this adding strength to the ball at this point and effectually closing the opening throughout the thickness of the shell. Instead of employing a machine for performing the rolling action provided with a groove of only one diaameter the same machine may have grooves of diflerent diameters.

I do not limit myself to the precise steps of the method above disclosed, one important point being, however, that the blank is formed with a flaring flange which is trimmed and upset to provide the beveled edge. By this trimming operation the edge is left comparatively smooth, the trimming action eliminating in large measure, or entirely, the irregularities in the edge of the blank existing as a result of previous operations thereon. I

What I claim is:

1. The herein described method of n aking one-piece sheet metal hollow balls conlisting in forming a blank of substantially cupshape with a flaring rim or edge, cutting said rim exteriorly to form an outside face of substantially cylindrical form concentric with the walls of the cup, and at a sharp angle to the inner inclined face of the rim, up-

setting said rim to lie in the plane of the wall of the cup and forming a coincident continuation thereof with the edge face inclined to the axis of the cup and tapering upwardly, transforming said cup-shaped body to an approximation of the form of a ball and leaving an opening tapering toward the center of the ball and then rolling said body to bring the inclined edge portions surrounding the opening together to close the opening, substantially as described.

2. The herein described process of making a one-piece sheet metal hollow ball consisting in forming a substantially cupshaped blank with an outwardly extending rim portion having its edge face at an invelihation to the main part of the Wall of said rim portion, upsetting the said rim portion to be coincident with the wall of the cup, whereby the edge face of said rim portion will be at an inclination to the axis of the cup, then upsetting the cup to an approxi mation of a sphere and then rolling the said sphere to bring the inclined edge face together to close the opening, substantially as described.

In testimony whereof, I afiix my signature.

JOSEPH HARRY GRUVER. Attest: i

J. WM. SHEFFER. 

